Section 1 (5-1) Classifying Rocks

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Vocabulary

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texture- the look and feel of the rocks surface
grains- particles of minerals that form rocks
igneous rock- it forms from the cooling of molten rock, which could be magma underground or lava on the surface
sedimentary rock- are formed when humus, or the remains of plants and animals are crushed together and form rocks
metamorphic rock- are formed when existing rocks are changed by chemical reactions, heat, and also pressure

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Outline

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Rocks

• a rock is a tough piece of the earth's crust
• rocks are made up of minerals and other materials
• rocks are like the earth's and moons building blocks
• on our planet they form
  • mountains
  • hills
  • valleys
  • beaches
  • ocean floor

Classifying Rocks

• when studying rocks geologists take a look at the
  • color
  • texture
  • and declare its chemical composition
• using the facts listed above geologists can classify a rock according to
  • its origin
  • where and how it formed

Rock Groups

• igneous rocks
  • it forms from the cooling of molten rock, which could be magma underground or lava on the surface
• sedimentary rocks
  • are formed when humus, or the remains of plants and animals are crushed together and form rocks
  • usually forms in layers underground
• metamorphic rocks
  • are formed when existing rocks are changed by chemical reactions, heat, and also pressure
  • metamorphic rocks mostly forms many very deep inside the earth